Power generation systems often include a power converter that is configured to convert an input power into a suitable power for application to a load, such as a generator, motor, electrical grid, or other suitable load. For instance, a power generation system, such as a wind turbine system, may include a power converter for converting variable frequency alternating current power generated at the generator into alternating current power at a grid frequency (e.g. 50 Hz or 60 Hz) for application to a utility grid.
Power converters that use switch mode, voltage sourced, Pules Width Modulation (PWM) methods to replace fixed speed mechanically throttled processes have been restricted to a severe tradeoff between operability and efficiency. Mechanical valves and bypass, as well as speed changers, are all part of present state of the art where very large power and reliability has not been proven in power electronics.
Large and costly, as well as wasteful, passive filters have been a part of the limits. Another is a restriction of voltage where single Insulated Gate Bipolar Transistors (IGBT), or their equivalents, are used. When Multiple IGBTs are used creating a high quality waveform becomes one of the concerns, since this helps to reduce the concerns of the passive filtering. Many complicated solutions are being proposed.
In view of these known issues, it would be advantageous, therefore, to develop a simpler method of achieving high voltage, low distortion power converters capable of variable frequency, small footprint, and high efficiency.